• Ocean and Polar Research
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• v.35 no.2
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• pp.69-83
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• 2013

Metal concentrations in creek water, sewer outlets and core sediments were analyzed to identify the potential origin of metal pollution and to evaluate the extent of metal pollution and potential toxicity of Lake Shihwa. Mean concentrations for dissolved metals in creek water and sewer outlets were 1.6~136 times higher than those in the surface seawater of Lake Shihwa. Metal concentrations in creek water from an industrial region were also higher than those from municipal and agricultural regions, indicating that the potential source of metal pollution in the study area might be mainly due to industrial activities. The vertical profiles of metals in core sediments showed an increasing trend toward the upper sediments. Extremely higher concentrations of metals were observed in the vicinity of Banweol industrial complex. The results of a geo-accumulation index indicated that Cu, Zn and Cd were highly polluted. By comparing the sediment quality guidelines such as TEL and PEL, six metals such as Cr, Ni, Cu, Zn, Cd and Pb levels in core sediments nearby industrial complex exceeded the PEL value. Mean PEL quotient (mPELQ) was used to integrate the estimate of potential toxicity for measured metals in the present study. Mean PELQs in core sediments from Lake Shihwa ranged from 0.2~2.3, indicating that benthic organisms nearby the industrial complex may have been adversely affected.

• Journal of Korea Water Resources Association
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• v.43 no.5
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• pp.455-469
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• 2010

Changes of geomorphology in alluvial river and vegetation recruitment on its floodplain downstream from dams are investigated both qualitatively and quantitatively focusing on the downstream of Andong dam and Imha dam on the Nakdong River. Results of the analyses of river morphology and bed material in the study site show a general trend of riverbed degradation with a max scour of 3 m and bed material coarsening from pre-dam value of 1.5 mm in D50 to post-dam value of 2.5 mm. Decrease in bed shear stress due to the decrease in flood discharge have caused vegetation recruitment on the once-naked sandbars. As result, the ratio of area of vegetated bars over total area of bars has drastically changed from only 7% in 1971 before the Andong dam (constructed in 1976) to 25% after it, and increased to 43% only three year after the Imha dam (constructed in 1992) and eventually to 74% by 2005. Analysis of the vegetation succession at Wicjeol subreach, one of the three subreaches selected in this study for detailed investigation, has clearly shown a succession of vegetation on once-naked sand bars to a pioneering stage, reed and grass stage, willow shrub and eventually to willow tree stages. At the second subreach selected, two large point bars in front of Hahoe Village seem to have maintained their sand surfaces without a signifiant vegetation recruitment until 2005. The sand bars, however, seem to have been invaded by vegetation recently, which warns river managers to have a countermeasure to protect the sand bars from vegetation invasion in order to conserve them for the historical village of Hahoe. On the other hand, recruitment and establishment of vegetation on the sand bars by artificial disturbance of the river, such as damming, can create an unique habitat of backmarsh in the sandy river, as shown in the case of Gudam Wetland, and may increase the biodiversity as compared with relatively monotonous sand bars. Last, the premise in this study that decrease in flood discharge due to upstream dams and decrease in bed shear stress can induce vegetation recruitment on the naked sand bars in the river has been verified with the analyses of the distribution of dimensionless bed shear stress along the selected cross section in each subreach.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.571-581
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• 2007

The mechanism of water pollution in Lake Shihwa, one of highly eutrophicated artificial lakes in Korea, has been studied using a numerical 3D physical-biochemical coupled model. In this study, the model was applied to estimate the contribution of land-based pollutant load to water quality of heavily polluted Lake Shihwa. The chemical oxygen demand(COD) was adopted as an index of the lake water quality, and the spatial distribution of an average COD concentration during the summer from 1999 to 2000 was simulated by the model. The simulated COD showed a good agreement with the observed data. According to reproducibility of COD, the high-est levels between 8 and 9 mg/L were shown at the inner site of the lake with inflow of many rivers and ditches, while the lowest was found to be about 5 mg/L at the southwestern site near to dike gate. In the pre-diction of water quality of Lake Shihwa, COD showed still higher levels than 3 mg/L in case of reduction of 95% for land-based pollutant load. This suggests that the curtailment of land-based pollutant load is not only sufficient but the improvement of sediment quality or the increase of seawater exchange should be considered together to improve a water quality in Lake Shihwa.

• Korean Journal of Environment and Ecology
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• v.1 no.1
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• pp.1-23
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• 1987

To investigate the forest structure of Mt. Bukhan. ranging from Seoul to Kyongkido, twenty plots were set up by the vegetation physiognomy and vegetation analysis was carried out. According to the leading dominant tree species in canopy stratum, forest communities were classified into three large groups of natural forest communities, semi-natural forest communities and artificial forest communities, and each of them covered 82.64, 7.03, and 5.71% of Mt. Bukhan area, respectively. Pure or mixed natural forest communities of Pinus densiflora and Quercus mongolica were major forest communities and covered 70.8% of Mt. Bukhan area. The important planted tree species were Robinia pseudoacacia, Pinus rigida, and Alnus birsuta and they were mainly planted at the southern slope and roadside. The degree of human disturbance of vegetation of 8, 7, and 6 area covered 82.64, 0, and 12.74%, respectively. According to forest dimensions, most of forest communities were young aged forests of which mean DBH was 20cm and canopy height below 10m. However, a few mature forest communities of Pinus densiflora or Quercus mongolica were found in the small area. The range of Shannon's species diversity of major natural forest communities, pure or mixed forest communities of Pinus densiflora and Quercus mongolica was 1.085~1.242. According to stand dynamic analysis by DBH class distribution, the present Quercus mongolica communities arid Robinia pseudoacacia communities may last long their present forest structure and most of other communities may be succeeded to Quercus mongolica communities, however, a few communities invaded by Robinia pseudoacacia and Quercus aliena-Quercus acutissima communities may be succeeded to Robinia pseudoacacia communities and Quercus aliena communities, respectively. DCA was the most effective method of this study. DCA ordination were showed that successional trends of tree species seem to be from Pinus densiflora through Quercus serrata. Prunus sargrntii. Sorbus alnifolia to Q. mongolica. Fraxinus mandsburica, F. rhynchophylla in the upper layer and from Zanthoxylum schinifolium, Lespedeza crytobotrya trough Rhus trichocarpa. Rh. verniciflua. Rhododendron mucronulatum. Rh. schlippenbachii to Acer pseudo-sieboldianus. Magnolia sieboldii, Euonymus sieboldianus.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.45-55
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• 2007

Flora, actual vegetation map, distribution area by the life form, primary productivity and annual primary production by the vascular hydrophytes and hygrophytes were investigated in the Upo wetland, Changnyeong-gun, Gyeongsangnam-do, Korea from May 2005 to March 2006. The flora of Upo, Mokpo, Sajipo, Jokjibyeol, Topyeongcheon upstream, and Topyeongcheon downstream were composed of 263, 233, 244, 182, 190, and 178 taxa, respectively. The flora of total study area was 85 families, 224 genera, 287 species, 42 varieties, 4 form, or total 333 taxa. Among them, hydrophytes, hygrophytes, and others were 38, 108, and 187 taxa, respectively. The life form of the vascular hydrophytes was classified as 20 taxa of emergent plants, 6 taxa of floating-leaved plants, 5 taxa of free-floating plants, and 7 taxa of submersed plants, respectively. There were 27 plant communities including pure population, mixed population, and etc. It is also found that Trapa japonica-Ceratophyllum demersum community occupies 60.64 ha, the largest area, and Salvinia natans-Ceratophyllum demersum community 32.91 ha, Zizania latifolia community 30.05 ha, and that the area of free-floating plants was the largest as 172.6 ha(47.9%) on the basis of life form. Total annual primary production of the vascular hydrophytes and hygrophytes was 1,383.3ton. That of the emergent hydrophytes was the most as 564.1 ton(40.8%), and those of the free-floating, floating-leaved, and the submersed were 484.1 ton(34.9%), 146.7 ton(10.6%), and 1.3 ton(0.5%), respectively, and the hygrophytes was 182.1 ton(13.2%). Since most plant species are fairly adapted to the present marsh environment, bad influences and change of species composition are expected by the artificial influences on the wetland such as fragmentation, reclamation, and introduction of the exotic species. Therefore, schemes and counterplans for the conservation and preservation of the marsh are demanded.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.1
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• pp.36-44
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• 2010

In order to rehabilitate forest sites damaged by wildfire via natural or artificial restoration, it is important to determine right tree species, which can acclimate to biogeoclimatic environment at the sites. The objectives of this study were to develop site index equation of different tree species for estimating forest productivity and to provide information on species selection for post-wildfire restoration. Site index equation was developed based on environmental information from wildfire damaged areas in Gangneung, Goseong, Donghae, and Samcheok, where were located in east coastal areas of South Korea. Despite the small numbers (4~5) of environmental variables used for the development of the site index equations, statistical analysis (e.g. mean difference, standard deviation of difference, and standard error of difference) showed relatively low bias and variation, suggesting that those equations can provide relatively high capability of estimation and practical applicability with high effectiveness. The small numbers of the variables enabled the model to be applied in a wide range of usages including determination of appropriate tree species for post-wildfire restoration. The estimation of forest site productivity showed the possibility of large distribution in east coastal region as the best site for Korean ash (Fraxinus rhynchophylla) and original oak (Quercus variabilis) that can be used for firebreak in the region. These results imply that damages by forest fire can be reduced significantly by replacing existing pure coniferous forests in the area with ones dominated by broad-leaved deciduous stands, which can play an important role as fire break and/or prevent a transition from surface fire to crown fire.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.1
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• pp.101-111
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• 2015

Stream restoration projects have become threats to riparian ecosystem in Rep. of korea. Riparian wildlife becomes isolated and the animals are often experience difficulties in crossing riparian corridors. The purposes of this study is to select suitable wildlife passages for wild animals crossing riparian corridors. Maximum entropy model and snow tracking data on embankment in winter seasons were used to develop species distribution models to select suitable wildlife passages for water deer. The analysis suggests the following. Firstly, most significant factors for water deer's habitat in area nearby riparian area are shown to distance to water, age-class, land cover, slope, aspect, digital elevation model, tree density, and distance to road. For the riparian area, significant factors are shown to be land cover, size of riparian area, distance to tributary, and distance to built-up. Secondly, the suitable wildlife passages are recommended to reflect areas of high suitability with Maximum Entropy model in riparian areas and the surrounding areas and moving passages. The selected suitable areas are shown to be areas with low connectivity due to roads and vertical levee although typical habitats for water deer are forest, grassland, and farmland. In addition, the analysis of traces on snow suggests that the water deer make a detour around the artificial structures. In addition, the water deer are shown to make a detour around the fences of roads and embankment around farmland. Lastly, the water deer prefer habitats around riparian areas following tributaries. The method used in this study is expected to provide cost-efficient and functional analysis in selecting suitable areas.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.850-857
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• 2015

This study was aimed to identify the characteristics of nest and breeding site conditions of Chinese Egret (Egretta europhotes) that breed in the uninhabited islets of the western coast of South Korea. It is expected that the information collected through this study can contribute to providing basic information required when building and managing artificial nests in their natural breeding habitats. Chinese Egrets make their nests in the shrub layers of Long Leaf Elaeagnus (Elaeagnus macrophylla), Arrow Bamboo (Pseudosasa japonica), and Baby Brier (Rosa multiflora). A total of 50 breeding nests of Chinese Egret were investigated in June and July 2013, with area-wise distribution as follows: Seomando (11 nests), Hwangseodo (14 nests), Mokdo (10 nests), and Napdaekiseom (15 nests). Vegetation coverage (cover, %), height from the ground to the top (height, cm), thickness from top to bottom of the nest (thickness, cm), reuse period, major axis (cm), minor axis (cm), and depth (cm) of each nest were measured. According to the results of the study on the nest characteristics of 4 breeding groups, the nests in Hwangseodo had the highest coverage, the nests in Mokdo were built in the highest places, the nests in Napdaekiseom showed the longest reuse period, and the nests in Mokdo had the greatest depth. The differences in height and reuse period were significant between Mokdo and Napdaekiseom. Moreover, there were significant differences in reuse period and depth between Seomando and Hwangseodo. There were significant differences in cover, minor axis, and depth between breeding groups that built nests on Arrow Bamboo (Mokdo and Napdaekiseom) and Baby Brier (Seomando and Hwangseodo). Nest characteristics of Chinese Egret were generally similar, while some variables showed different values for different breeding groups.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.105-117
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• 2018

This study conducted health assessment and multivariate vegetation analysis using the riparian vegetation index in 30 sites of the Geumgang mainstream and Mihocheon to obtain practical data on the river management of the Geumgang. The result showed that the number of plant communities was 54. The flora was 75 families, 185 genera, 243 species, 2 subspecies, 21 varieties, 2 varieties, and 268 taxa. The riparian vegetation index was 38.3 (3.3; G-D1 ~ 66.7; G-U2, G-U4, and G-M3), and the health of the rivers in this area was evaluated as normal (grade C). The health of rivers was the highest in the upper stream of Geumgang mainstream and lowest in the downstream of Geumgang mainstream. The relationship between riparian vegetation index and chlorophyll-a content was low. The riparian vegetation was divided into five groups of Digitaria ciliaris colony group, Salix gracilistyla colony group, Erigeron annuus colony group, the group dominated by Humulus japonicus, Salix koreensis, Miscanthus sacchariflorus, and Phragmites japonica colonies, and the group dominated by Conyza canadensis and Echinochloa crusgalli var. echinata colonies. They had the similar health conditions. The CCA analysis showed that the environmental factors affecting the distribution of vegetation were physical factors such as vegetation area, artificial structure area, waterway area, branch width, channel width, and bank height and the biological factors such as the number of species. As such, it is necessary to maintain the health condition through continuous monitoring where the health condition is high and to apply active measures such as ecological restoration where the health condition is low.

• Korean Journal of Environment and Ecology
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• v.17 no.4
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• pp.324-336
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• 2004

This study was achieved to present ecological administration plan by analyzing vegetation structure and condition rating class(environmental damage degree) of Sangnim Woods Natural Monument in Hamyang-gun, Korea. In vegetation structure part, actual vegetation was classified by 22 patterns and Quercus serrata Carpinus tschonoskii community(31.8％), Quercus serrata community(14.6％) ranged extensively. Main plant community was 8 types, and is fractionated by 13 plant communities according to stratigraphy development degree it is Quercus serrata community, Quercus serrata Carpinus tschonoskii community, Quercus aliena community, Quercus acutissima community, Carpinus tschonoskii community, Carpinus tschonoskii Quercus serrata community, Zelkova serrata-Quercus serrata community, and Planted area with korean landscape woody plants. Age of old growth trees that diameter of breast height over 38cm was 61∼77years. In condition rating class, area of class 3 was 51,960$m^2$(32.8％), area of class 4 was 6,583$m^2$(3.5％), and area of class 5 was 4,086$m^2$(2.6％) and gross area of class 3∼6 need artificial restoration was 61,619$m^2$(38.9％). Considering actual vegetation, plant community structure, and condition rating class biotope was classified by total 14 types. While distribution area of Queens spp. old growth forest of shrub damaged(51,246$m^2$, 32.4％) and deciduous broad leaved old growth forest of simple-layer structure(19,906$m^2$, 12.6％) is large and that of deciduous broad-leaved old growth forest of multi-layer structure(2,085$m^2$, 1.3％) and Queens spp. old growth forest of multi-layer structure may have to manage with user control by administration plan for stabilization of Sangnim Woods ecosystem for long-term. Also, both vegetation of shrub damaged and simple-layer structure as negative restoration area should be restored for ecological succession and both grassland and planted area with korean woody plants as positive restoration area should be revegetated by using ecological planting model of native vegetation structure in Sangnim Woods.